Swapping Gears: Raising my skoolie's top speed and getting better mpg
ฝัง
- เผยแพร่เมื่อ 30 ก.ค. 2024
- Changing the rear end ratio of your skoolie's differential is a great way to transform it from a city rumbler to a highway cruiser, all while getting better mpg, making less noise, and wearing on the engine less
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Timestamps for y'all
0:00 intro
1:26 ratio education class
6:40 what does a differential look like on this bus?
7:06 high level plan for how we're gonna do this
9:34 tools needed
14:34 gawkin at a transmission jack
15:22 gawkin at the new diff and preparing for fluid drain
16:50 opening er up
17:01 a visitor arrives
17:30 back to work
22:12 test drive
24:06 initial thoughts
25:18 closing
One thing you didn't mention is that with the higher (numerically lower) rear end ratio you will give up some acceleration, but let's be real, any bus is a slug when it comes to acceleration, it's the nature of the beast. Overall I think it was a very good trade off. Keep the good stuff coming.
It's a good idea to pull the fill plug before you drain the oil. It sucks having a dry diff with no way to fill it because the fill plug is seized.
Glad I found your channel Chuck. The wife and I are planning on a conversion in the next year or two. Thanks for breaking everything down the way you do. ❤
Dude, you’ve GOT to be kidding me, I just replaced my diff this week. Telling you Charlie, synchronicity at it’s best. Having a AT545 like yourself I went from a 4.78 to a 4.10 for a 14% increase.
Nice how do you like it?
How's the 4.10 gear
I currently have a 4.78. 58 mph was top speed. Can't wait to get it all done to see how she does
Nice elegant breakdown!
Spot on per usual.
I'm excited to see you finish the inside
At least the cops didn't show up in this video!!!
Better call 'em.
@@bloodybonescomic better call Saul!!
Another great one done. That is one beautiful bus!
That army green color is epic!
Excellent content. You address topics that nobody else dares to discuss. Good work.
Extremely helpful tutorial. Thank you!!
Thank you Chuck for another amazing video! I greatly appreciate you sharing your experince and insight as well as breaking things down and terminology into a learnable session. With videos like these is like hitting gold. I love watching your videos because i always learn something new! I've always loved school buses since i was a kid and always wanted one of my own. And this helps me understand how they are builtso once i began my skoolie venture I'll have the resources to build one! Thank you for sharing your resources and sites as i bookmarked them now. Again this has been very very helpful and resourceful!
Thanks Chuck :)
Great video. Looking forward to your MT 643 swap video. 👍
still can't get over how good that color is on the bus.
Me neither!
Wow vety cool this reminds when i worked for a shop and they worked on diesels taught me alot and that i rememberec what you were showing on what to do!!
Great work… I love the bus color too!
Same. That color is nice!
Now I gotta see what mine has for differential 😂. Chuck yer killin' me.. .but don't stop I love my schoolie
I changed my mine from 6.14 to 4.78. I also have a 5 speed
I have a 1980 stepvan 350gas motor(matco tool truck)that had 6.2 gears in it with a 1:1 final drive.
I swapped in a totally different rear axle and went with 3.73 gears and went from dually s to singles.
I can now drive 70mph @3k rpm vs 60mph @ 5k rpm...it was bad.. 5mpg b4.
8-10mpg now.
Such a nice change, just have to fine tune the carb a bit more to get better mpg.
But not bad for a 13k lb van ,house,shop.
I enjoy the thoroughness of your vids 👍
Wow lookie there lookie there. Nice .
Great paint
Just finished binging all your skoolie conversion videos in the playlist in the past 4 or so days and am so happy to have stumbled across you, Chuck. You have given me so much amazing info for when I start my build. I haven't gotten my bus yet, but thanks to your videos I feel so much more confident about doing almost all of it myself, with some help from friends of course, except for the roof raise. Do you happen to know any people out near East Tennessee that would be able to do it that you would approve of?
Sure don’t! Sorry
I like that the lower gears don't seem that much affected. I was thinking of adding a sixth gear to my kei van, but maybe a new differential is the way to go. It has a beefy 660 cc engine, so it can handle 65 mph if the wind doesn't knock it over. Great video, I learned a lot
i dig the exhaust out the side to make for more storage under the buss. ill becopying the idea
The downside with the AT545 transmission (I think you said) is now going to be producing even more heat. Another reason to get that locking torque converter as soon as possible (or buy a bus that already has one).
A lot of people out there have MD3060s and you can do a lot by getting 6th gear unlocked, if it isn't already. My bus has 5.38 gear ratio, but with 6th gear unlocked, I still get great acceleration and also 1800 rpm cruising.
It is however also may not the best to have the driveshaft and diff spinning that fast. Jury still may be out on that one.
Before scooting the differential under the bus, test fit the axles into the sides of the differential. There is a variety of axle splines, some times more than one choice, It sucks to find out the axles don’t work AFTER the the diff is bolted in.
he mentions that
Can you please do a follow up video after taking it up a grade or two. Curious to see how it affects your uphill speed/temp
Same. With the 545. I'm gonna do a gear swap in mine. Almost same bus as his. I think 3.90 or 4.11 is as low as ima go. I've been told the tq is there. But you gotta unleash some HP. Easily and cheaply mod out a 12v to 400
id recommend the 3.9 if youre going to turn your engine up. i have a dt466 with 4.1 gears and a 6 speed alison and it runs 2300 rpms at 68ish. smaller tires though@@withQandZ
@@thisismov I'm already pushing more than the 545 will handle. Fuel plate. Governor springs, bigger turbo, 24v manifold. Injectors delivery valves
@withQandZ how so you unleash the hp? Dt466e and at545 in mine.
@compasslife6658 well I have a 12v cummins. Mine is all mechanical. I've got a different fuel plate, turbo upgrade, performance manifold port and polished, governor springs, afc spring kit, injectors, p pump delivery valves. And still a little more to come. You, on your engine. You can actually turn your engine up and take the governor away on a computer. You can buy the plug in and software for it. My buddy did. Great for real time diagnostics.
Good tutorial. I would add using silicone buy Right Stuff. Little more expensive but is indestructible and peace of mind it wont ever leak.
I have a 2001 7-window International Bluebird skoolie and I've never been in the fast/passing lane. I am geared pretty good and governerned at 70mph. I like 60-65mph.
I need to do the same with my international. Was thinking of increasing the wheel size as a cheaper option but i have dayton style hubs. Would like to jump from 9r22.5 to 10r24.5.
I see what looks to be the stud piloted wheel end system, how lovely ! ... but that is the era and so no choice there unless the hubs and wheels were changed over for a conversion $$$. I was curious as to the condition of the brakes/s cam shafts and bushings but also the hub bearings given the condition of the oil and the howl in the diff could mean metal contamination has found its way into the bearings. I know its a lot of work but it would actually be nice to tear into the hubs and inspect/replace bearings if in question and obviously the hub seals and since its apart replace the s cam bushings and grease seals ( or s cams if they are worn much ) and yes probably the slack adjusters and new spring brake pot assemblies as well and the irony is a new set of brake shoes would be so minor in cost compared to what I just listed off.
Chuck have you checked to see what your mpg is after the differential swap? I'm curious how much it improved.
nice color chuck....😎
Love your videos! When are you gonna do a "how to paint the exterior" vid? Your bus looks great.
Already did
Hi Chuck,
Have you thought about 2 toning your bus with a nice tan on the bottom section?
Personally I think it would set it apart in a tasteful manner.
I have a Ford 4WD pickup that we bought from the original owner.
The factory exterior paint is Silver, ( we don’t care for Silver, Grey, Charcoal Grey or Black), so I wanted to break up the paint.
I decided to 2 tone it out with Red metallic on the lower section.
It’s a 1 of a kind now and I’ve had several people compliment me on the 2 tone paint.
I also had it reupholstered in Red with black trim and stitching.
We mainly use the pickup for work around our property so even though it’s a 2011 year model it has only 36K miles and still looks showroom new.
I think Tan 2 tone would really set off your bus
if you have an Allison transmission that has a locked 5th and/or 6th speed transmission would unlocking the extra levels on the transmission help as well with the increasing speed and fuel efficiency?
Great video!
Hey Charlie,
I’m a new Skoolie owner and this would help me out greatly. How much would a service like this cost me if I were to buy the differential separately?
Also I love the videos. I’m actually getting the equipment together now to add a Trailer hitch after watching your video. Thank you!!
A question or two? Do you know of any other way to better fuel milage?
Also, have you ever considered replacing the sheet metal on the bus for fiberglas?
In our next video we go full all wheel drive…
I was wondering how many hours you think it takes to demo and cut and raise the roof 12in and then do the floor on a 35 ft bluebird
Great videos as always Chuck. I got lucky with my bus, I have 4.11 ratio. She's great on the expressway, and 10 mpg. Hey! did you straight-pipe that bus? If so is it really any louder?
nice! its still got a muffler, it just comes out the side to make room for my storage box
Does this change out do anything to your ability or power going up hills? If not how could I improve that in my bus? It's a T444E, with Allison 2000.
Having the skills to do a job like that are so good - and far fewer kids these days are picking them up. Great job. This is probably a stupid question (and reflective of my complete lack of mechanical abilities) but did you have to change the speedo or is that tied directly to one of the wheels and not the driveshaft?
I don't know what's common in America but in Europe yes, the speedometer is usually driven from the gearbox (transmission) so the ratio would need to be changed there too.
We used to barely be able to make out what you were saying and now it doesn't sound like you're in a blender, so there's that.. 😂
If someone had to pay for the labor on this rear end change what would you guess the cost?
Don't you also need to have your speedometer recalibrated
What RPM were you doing at 70? Most of the DT466 peak torque at about 1300 from what I can see
Good info Chuck as always. Question..... I also have the Cummins 5.9 1st gen with the Allison AT545 . I can financially swing the gear change but not the MT643 so what I want to know is how will the gear change effect lets say a 7 or 9 grade mountain ?
its gong to depend on your weight and the HP rating of the engine. It likely means youll be one gear lower than you would otherqwise be but might not affect uphill driving that much
I can tell how much quieter it is and the ole girl seems to be moving down the highway pretty quickly.
Lkq Crystal River Florida, where I be now
This is a fun project
I just swapped mine at a rest stop after two teeth on my pinion gear blew out.
Not a fun project for me 😬
So HOW did you choose the 3.73 ratio ?
could you please show what you did with the odometer, how and where to change the settings there and where did you get the parts?
Haven’t done that yet
Loved the video Chuck but you are going to have to dress up more if you are going to stand next to that beautiful paint job. Time to celebrate and have a Margarita. :>) kenknaell
Have you driven this enough to get an idea on how much your MPG has changed?
Increasing the horsepower in any diesel will also increase your fuel mileage because the motor is not working as hard.
Lol! Nice try.
@@corby404 Really? It's worked on all the semis I've been driving for over 23 years.
Does Kevin Rutherford agree with you on this?
@@corby404 I don't know or care. He's not the end all to be all of the trucking industry.
He's a tool but an expert on fuel mileage.
So, i think i missed where you said what gear ratio you changed to. I have a 4.78 gear rear. 400hp 12v with an Allison 2000 6 spd. Did you go to a 3.73? I was thinking to do a 3.90 or even 4.11. Thoughts?
3.73....a 400hp 5.9? wow. you already have double OD
@ChuckCassadyYT ya. Modified p-pump, injectors, turbo upgrade, 24 v manifold port and polished. Allison 6 spd with HD torque converter. I was gonna run 3.90 gears
@ChuckCassadyYT but I've read extensively. That you can fudge up your trans set up especially having that double OD if you run too low of a gear
I also have the AT545 with a 12 valve cummins
Get an allison 6 speed. Close ratio. Run you 400-800 used. Rebuild is super easy
@@withQandZ I was thinking an allison 2400
@@_WADE13x it's the same. Just stay away from 2500. Or any close ratio. It's not going to shift how you want. And won't respond well to the 12 v tq curve
@@_WADE13x you gotta make sure it has the 6th gear already installed. Ppl will say "oh you just gotta get Allison to "unlock" it. Which isn't the case unless it already had the 6 spd valve body
How do you know how much to decrease the ratio by?
Work backwards from an intended top speed or cruising speed & then see what ratios are available. You will be recalculating several times, you need to put quite a lot of thought into it before you buy anything.
Phone the manufacturer to check the engine has enough power for that speed, almost all will be fine for increased cruising speed, maybe not for increased top speed as air resistance goes up enormously with speed.
While you've got the calculator out also check the speed of your lowest gear - if your top speed will be 20% higher your lowest speed will be 20% higher too & you might not be able to start on steep hills.
@@alanhat5252 thank you!
How do you change gears in a coffin car?
You have to work the graveyard shift
@@JoeandEmmaLee lol
Oh maaaaan
I think my 6.44 gear ratio is gonna keep me going slow ... 🙂
Why not just unlock the 6th gear? 🤓
because the differential needs changing anyway.
His transmission only has 4, there’s nothing to unlock in an AT545
3.73 gears ? Wouldn’t a 3.55 do better for better efficiency? No it wouldn’t have as much poop, but one would think that it would get better fuel economy
Ejecto-diff…
Wow, $1K for a reman 3rd member is cheap
Your going to a higher ratio not lower chuck
look at the calculations on the whiteboard early on.
The lower the number, the higher the ratio. IE 4.10:1 is a higher ratio than a 5.38:1 gear set.
put a spoiler on it...
Now I gotta see what mine has for differential 😂. Chuck yer killin' me.. .but don't stop I love my schoolie